Black Country MP Tom Watson urged Labour to unite around new leader Jeremy Corbyn as he succeeded in his bid to become the party's Deputy Leader.

But Mr Watson, MP for West Bromwich East, warned that Labour was at a "critical moment" - and the public are "sick of politics".

Left-wing London MP Jeremy Corbyn won a stunning victory, receiving 59 per cent of "first preference" votes in an election where voters could pick multiple candidates.

The result was a rejection of candidates associated with recent Labour governments led by Tony Blair and Gordon Brown.

Some Labour MPs, such as Dudley North MP Ian Austin, had fiercely criticised Mr Corbyn during the election contest and warned that he would be unable to lead Labour to victory din the General Election due in 2020.

In a speech following his election, Mr Watson urged: "I promised to back our new leader 100 per cent. I plan to do exactly that and I ask you to do the same.

"Only through unity comes the strength we need to fight the Tories. And be in no doubt, in the Tories' second term, Labour is the last line of defence for the millions of people who suffer at their hands. Only Labour can speak for the real Britain.

"We haven't always but thats what we have to do again.

"We can and we will, I promise."

But he warned: "The Labour Party is at a critical moment. And great movements like ours endure by understanding and embracing moments of such change."

The public was "sick of all politics," he said.

"And even our own people are sick of the old ways of doing politics. That is the biggest challenge we face as a party."

Mr Watson also warned that Labour must always be pro-businesses.

And he insisted Labour would win the next election, saying: "We will win in 2020”.

Jeremy Corbyn has won the leadership of the Labour Party by a landslide, taking almost 60% of more than 400,000 votes cast.

He said: "The fightback now of our party gathers speed and gathers pace."

In a result which marks a fundamental change of direction for the party, the Islington North MP defeated rivals Andy Burnham, Yvette Cooper and Liz Kendall in the first round of counting, taking 251,417 (59.5%) of the 422,664 votes cast.

His victory was cheered loudly by supporters at the QEII conference centre in Westminster, who had greeted him to the event by singing the Red Flag.

After 32 years on Labour's backbenches, the 66-year-old won only a handful of votes from his fellow MPs but was swept to victory in the race to replace Ed Miliband by a surge of enthusiasm from members in the country as well as new "registered supporters" who paid £3 to secure a vote.

He now faces the massive challenge of forming a shadow cabinet which will deliver his anti-austerity, anti-war policies without splitting the party. Already senior figures including shadow chancellor Chris Leslie, shadow education secretary Tristram Hunt and Ms Kendall have said they will not serve under him.

Mr Corbyn must also prepare to face David Cameron in the House of Commons for his first Prime Minister's Questions on Wednesday.

Who is Tom Watson?

Tom Watson

Tom Watson, the MP for West Bromwich East, was an ally of Gordon Brown, the former Labour leader and Prime Minister, and had a reputation as a behind-the-scenes fixer.

He was a defence minister in Tony Blair’s government but resigned when heand became one of the Labour MPs openly calling for Tony Blair to set a date for standing down, forcing Mr Blair to quit Downing Street earlier than expected.

Mr Watson returned to government as a junior minister once Gordon Brown took over as Prime Minister. However, his real power during this period stemmed from his close personal relationship with Mr Brown, and he was often in Downing Street offering advice

He served as Labour’s Deputy Chair while Ed Miliband was party leader, but resigned from that post. He had concerns about the way Mr Miliband led the party but kept them to himself.

Many people probably know him best as the MP who campaigned from the backbenches to expose phone hacking by journalists, as well as calling for an inquiry into child abuse.

At times Mr Watson has been seen as a divisive figure in the party - but this partly reflected the divisions within Labour caused by the personal rivalry between Mr Brown and Mr Blair, which are now far in the past.

Some Labour MPs hope he will hold the party together in his new role, during what may be a difficult period.

But there is still antipathy towards Mr Watson from some quarters stemming from what is seen as his close relationship with Len McCluskey, General Secretary of the Unite Union, which threw its weight behind Mr Corbyn during the leadership election and made the best possible use of the new election system which allowed candidates to sign up supporters to vote in the ballot for just £3.